Stylus for talking-machine.



A. KNIPPENBERG.

STYLUS FOR TALKING MACHINES.

APPLICATlON FILED MAY 20. 1915.

Patented Oct. 24, 1916.

fizvemww t t T@ It AUGUST KNIPPENBERG, 0F ARNSTAIDT, GERMANY.

STYLUS FOR TALKING-MACHINES.

it 30%, W39.

Specification of Letters Patent.

Application filed May 20, 1915. Serial No. 29,360.

To all whom it may concern:

Be it known that T, AUGUST KNIPPENBERG,

a subject of the German Emperor, residing The present invention relates to improve-- ments in styluses for talking machines, and more especially to those used in connection with the disk records of gramophones.

According to the present invention, the stylus embodies an operative portion which is cylindrical andthe bottom or end of which is rounded, the angle of the bend lying in a plane transverse to the direction of the sound-groove in the disk, the slanting position of the cylindrical portion of the stylus causing it to present to one side wall of the sound-groove a bearing surface of greater extent than that presented to the soundgroove by the opposite side of the stylus, wear of the groove in the disk and stylus being thus minimized, resulting in increasing the durability of bath the stylus and the records. 1

A further feature of the invention consists in providing the stylus with means for insuring its correct insertion into the stylus holder in order that the stylus will be accurately positioned relatively to the record. It is well known that styluses of the kinds ordinarily used for talking machines present the objection that they can be used in the reproduction of only one or two records. Repeated efforts to produce more durable styluses have proved unsuccessful, because of the fact that styluses as usually shaped and positioned wear ofl more at the sides thereof than at their ends. Moreover, the ordinary styluses do not possess the necessary strength to transmit the sound-waves to the diaphragm, owing to the fact that their points must be as narrow as thesoundgroove in the disk. A. stylus of thls character which is worn off at the side allows play of the stylus laterally in the sound-groove, producing discords. and noises, and 1t unduly wears and destroys the sound-groove 1n the disk.

A stylus embodying the present invention on the contrary always presents substantially the same contact surface to the walls of the sound-groove of the gramophone disk. The shape of the rounded point does not change to any appreciable degree. 1e,

when often used, the stylus is ground off at the end, which has the effect of shortening its length, it maintains the same characteristic engagement withv the groove of the disk, and because of the fact that the side of the stylus toward the periphery of the disk has a surface of increased area to engage the corresponding wall of the sound groove in the disk, a good contact between these parts is maintained and lateral play or rattling of the stylus in the groove is prevented. Fineness in tone and delicacy of reproduction are thereby attained. The stylus shapes itself in accordance with the shape of the sound grooves in the disk and it maintains good contact therewith. Owing to its great bearing surface, its wear is considerably diminished. The stylus is sufficiently rigid to transmit, through its slanting cylindrical portion, the tones to the-diaphragm, notwithstanding its sensitiveness. The slope of the cylindrical portion of the stylus may vary within certain limits.

For the purpose of insuring correct application of the stylus to the holder, the stem of the stylus is provided with a flattened or widened surface, which surface is preferably provided with a mark for indicating the correct position of the stylus in the holder to present the stylus in proper relation to the gramophone disk.

An embodiment of a stylus for talking machines constructed in accordance with the present invention is shown in Figures 1 and 2 of the accompanying drawing.

Fig. 1 shows the stylus. in cooperative relation with a record disk of a gramophone. Fig. 1 shows the stylus as viewed from one side in Fig. 1. Fig. 2 shows the stylus, on a larger scale, fitted into its holder and in coiiperative relation with a record disk. Figs. 3 and 4 represent styluses of a type heretofore used having a conical point, Fig.4 showing the wear and the resulting deformation of the point.

The stylus in that embodiment of the invention shown comprises a stem or shank 1, the upper portion of which is adapted to be clamped in the stylus holder 3, the stem being provided at an intermediate point with a widened or flattened web 2 for the purpose of insuring proper application of the stylus in the holder. The stem tapers off into a cone 4, it thence continuing as a cylindrical part 5 which has an inclination at an obtuse angle of, for example, 150

Patented @ct. 2a, rare.

to 160. Owing to the slanting position of the cylindrical portion, the stylus is, to some degree, resilient vertically, thereby enabling the stylusto easily follow the undulations in the sound-groove of the disk. The point or lower end 6 of the cylindrical part of the stylus is rounded off, as shown in Fig. 2. Because of the slanting position -of the cylindrical part 5, the stylus presents at the side 7 thereof (the right-hand side in Fig. 2) a greater bearing surface to the respective side of the groove of the disk than that presented by the other side of the stylus, and this insures a perfect guiding of the stylus in the grooveof the disk.

The ordinary styluses for talking machines having a conical point 8 (Fig. 3) cut or unduly wear the groove in the record disks, and also the styluses wear off in an uneven manner, as shown at 12 in Fig. 4, this wear of the ordinary type of stylus being due not only to the engagement of the sides of the stylus with the side walls of the sound-groove of the record but also to the force applied by the groove in the disk to the stylus to shift the stylus and the relatively heavy tone arm and sound-box toward the center of the disk as the stylus follows the spiral sound-groove. In consequence of this wear, such Styluses continually play or chatter in the groove of the disk, the Wear of the stylus and the walls of the grooves in the disk being rapid, producing noises and discords and rendering the life of the record disks short. These defects are avoided by the present invention.

In order to enable the stylus to be easily and quickly set in correct position in its holder, the front side of the stylus .is provided with the widened or flattened face 2 which is preferably provided with an indicating mark 9. I

The dotted lines 11' in Fig. 2 show diagrammatically the gradual wear of a stylus embodying the present invention having an oblique, cylindrical part 5. The wear merely shortens the length of the stylus without appreciably changing its shape, and such wear may be continued until it reaches the cone. The line 12 in Fig. 4 shows the quick, uneven, lateral wear of a stylus of the ordinary type when used for only one record disk, such wear rendering the stylus useless for further reproduction.

I claim 1. -A stylus for use with gramophone records having a cylindrical portion bent laterally relatively to they length of the sound-groove in the record at the point of engagement of the end of the bent portion therein;

2. A stylus for use with gramophone records having a cylindrical bent portion inclined relatively to the surface of the record and disposed transversely of the sound-groove at the point of contact of the bent portion therewith, the end of said bent portion being rounded to operate in the sound-groove in the, record.

3. A stylus for use with gramophone records, said stylus having a cylindrical portion bent laterally with respect to the sound-groove in the record at the point of contact of the stylus therein and having a widened portion occupying a predetermined relation to the laterally bent portion of the stylus for insuring correct positioning of the bent portion of the stylus relatively to the sound-groove in the record.

In testimony whereof I have hereunto set my hand in presence of two subscribing witnesses.

AUGUST KNIPPENBERG. 

